Expandable balloon sheaths

ABSTRACT

A tubular sheath for enclosing an expandable balloon attached to the distal portion of a catheter encloses and protects the expandable balloon. The tubular sheath is configured to be slidable and removable from the catheter. The tubular sheath may include a longitudinal splitting element that is removable as a result of a force applied to the longitudinal splitting element. The longitudinal splitting element is configured to split the wall of the tubular sheath in response to the force. Alternatively, the tubular sheath may include a gripping portion that has relatively poor cohesive strength to adjacent portions of the tubular sheath. The tubular sheath is configured to be removable in response to a force applied to the gripping portion.

TECHNICAL FIELD

This disclosure relates to medical sheaths, and more specificallyexpandable balloon sheaths.

BACKGROUND

Some medical treatments include the use of inflatable balloons. Theexpandable balloon may be inserted in a patient, such as within thevasculature of a patient, and navigated to a target site to be treatedwithin the patient. Some expandable balloons may be fragile, such thatit is easy for expandable balloons to incur damage during the insertionprocess. Further, some expandable balloons include coatings, such asdrug coatings, which may be damaged or lost during insertion and/ornavigation to the target site.

SUMMARY

In some aspects, this disclosure describes a medical device including atubular sheath for enclosing an expandable balloon. The tubular sheathmay be used with a catheter having an expandable balloon attached to thedistal portion of the catheter, such that the tubular sheath enclosesand protects the expandable balloon. The tubular sheath may enclose theexpandable balloon during at least shipment and pre-insertion handlingof the expandable balloon. The tubular sheath may be configured toenclose the expandable balloon up to and substantially through theprocess of inserting the expandable balloon into the body of a patientthrough an introducer sheath. The tubular sheath may be configured to beslidable and removable from the catheter. The tubular sheath may includea longitudinal splitting element and may be configured to be removableas a result of a force applied to the longitudinal splitting element.The longitudinal splitting element may be configured to split the wallof the tubular sheath in response to the force. Alternatively, thetubular sheath may include a gripping portion that has relatively poorcohesive strength to adjacent portions of the tubular sheath. Thetubular sheath may be configured to be removable in response to a forceapplied to the gripping portion.

In a first example, aspects of the disclosure relate to a medical devicethat includes a catheter configured to navigate vasculature of a patientafter insertion through an introducer sheath inserted in the patient,the catheter comprising a distal portion and a proximal portion. Themedical device also includes an expandable balloon that is attached tothe distal portion of the catheter and a tubular sheath configured toenclose the expandable balloon. The tubular sheath includes at least onelongitudinal splitting element within a wall of the tubular sheath, theat least one longitudinal splitting element being configured to splitthe wall of the tubular sheath in response to a force greater than athreshold force upon the at least one longitudinal splitting element.The at least one longitudinal splitting element extends from a proximalend of the tubular sheath to a distal end of the tubular sheath.

In a second example relating to the medical device of the first example,the at least one longitudinal splitting element includes a wire embeddedlongitudinally along a length of the tubular sheath, the wire configuredto extend out from at least one of the proximal end and distal end ofthe tubular sheath, wherein the wire is configured to split the tubularsheath as a result of pulling the wire out from the wall.

In a third example relating to the medical device of the second example,the medical device includes a tab that is attached to an end of the wirethat extends out from the at least one end of the tubular sheath.

In a fourth example relating to the medical device of the first example,the at least one longitudinal splitting element includes two or moresets of holes that extend longitudinally through a wall of the tubularsheath from the proximal end of the tubular sheath to the distal end ofthe tubular sheath, wherein the two or more sets of holes are configuredto split the tubular sheath as a result of stressing the tubular sheathalong the two or more sets of holes.

In a fifth example relating to the medical device of the fourth example,each set of holes includes two or more holes that are arranged radiallyfrom an inner surface of the tubular sheath to an outer surface of theinner sheath.

In a sixth example relating to the medical device of the fourth andfifth examples, the tubular sheath includes one or more grooves thatextend radially in from an outer surface of the tubular sheath andextend longitudinally from the proximal end of the tubular sheath to thedistal end of the tubular sheath, wherein each groove is radiallyin-line with one of the two or more sets of holes.

In a seventh example relating to the medical device of any of the fourththrough sixth examples, sets of holes are arranged 180° apart across thelongitudinal axis of the tubular sheath.

In an eighth example relating to the medical device of any of the firstthrough seventh examples, the tubular sheath includes at least one ofpoly(tetrafluoroethylene), high density polyethylene, or low densitypolyethylene.

In a ninth example relating to the medical device of any of the firstthrough eighth examples, a thickness of the wall of the tubular sheathis substantially constant throughout the tubular sheath.

In a tenth example relating to the medical device of any of the firstthrough ninth examples, the medical device further includes a Luerfitting at a distal end of the tubular sheath, wherein the Luer fittingincludes a structural weakness aligned with the at least onelongitudinal splitting element to enable the Luer fitting to becontrollably split along the structural weakness.

In an eleventh example relating to the medical device of any of thefirst through tenth examples, the tubular sheath is configured to bereceived by the introducer sheath during insertion of the catheter intothe introducer sheath such that the tubular sheath remains stationaryrelative to the introducer sheath while sliding proximally relative tothe catheter as the catheter is inserted distally at least until theexpandable balloon is fully inserted into the introducer sheath withoutsubstantial contact between the tubular sheath and the expandableballoon.

In a twelfth example, aspects of the disclosure relate to a medicaldevice that includes a catheter configured to navigate vasculature of apatient after insertion into an introducer sheath inserted in thepatient where the catheter includes a distal portion and a proximalportion, an expandable balloon that is attached to the distal portion ofthe catheter and a tubular sheath that includes a gripping portion. Thetubular sheath is configured to enclose the expandable balloon and thegripping portion of the tubular sheath has relatively poor cohesivestrength to adjacent portions of the tubular sheath such that thetubular sheath is configured to be split along the gripping portion toenable the tubular sheath to be splittably removable from the catheter.The gripping portion of the tubular sheath extends from a proximal endof the tubular sheath to a distal end of the tubular sheath and thegripping portion of the tubular sheath extends through a thickness of awall of the tubular sheath.

In a thirteenth example relating to the medical device of the twelfthexample, an external surface of the expandable balloon includes a drugcoating.

In a fourteenth example relating to the medical device of the twelfthand thirteenth examples, the expandable balloon is in a deflated stateon the distal portion of the catheter and a diameter of the inner lumenof the tubular sheath is configured to be greater than an outer diameterof the expandable balloon in the deflated state.

In a fifteenth example relating to the medical device of the fourteenthexample, a length of the tubular sheath along the longitudinal axis ofthe tubular sheath is greater than a length of the expandable balloonalong a longitudinal axis of the expandable balloon in the deflatedstate.

In a sixteenth example relating to the medical device of any of thetwelfth through fifteenth examples, the expandable balloon is apercutaneous transluminal angioplasty (PTA) balloon.

In a seventeenth example relating to the medical device of any of thetwelfth through sixteenth examples, the gripping portion of the tubularsheath includes a first material and adjacent portions of the tubularsheath include a second material, where the first and second materialare configured to have a relatively poor bond to each other and thetubular sheath is configured to be splittable as a result of pulling thegripping portion away from the adjacent portions.

In an eighteenth example relating to the medical device of theseventeenth example, the medical device includes a tab that is attachedto the gripping portion of the tubular sheath at an end of the grippingportion to facilitate pulling of the gripping portion.

In a nineteenth example relating to the medical device of theseventeenth and eighteenth examples, the first material is a differentcolor than the second material.

In a twentieth example relating to the medical device of any of thetwelfth through sixteenth examples, the gripping portion of the tubularsheath includes a first material and adjacent portions of the tubularsheath include a second material, where the first material has a greatertensile strength than the second material.

In a twenty-first example relating to the medical device of thetwentieth example, the medical device includes a tab that is attached tothe gripping portion of the tubular sheath at an end of the grippingportion to facilitate pulling of the gripping portion.

In a twenty-second example relating to the medical device of any of thetwelfth through sixteenth examples, the gripping portion and theadjacent portions converge at two parallel lines of perforations thatextend longitudinally from the proximal end of the tubular sheath to thedistal end of the tubular sheath and each line of perforation cutsthrough the wall of the tubular sheath. The medical device includes atab that is attached to the proximal or distal end of the grippingportion and the tubular sheath is configured to be splittable as aresult of pulling the tab and disengaging the first material from thesecond material.

In a twenty-third example relating to the medical device of any of thetwelfth through twenty-second examples, the tubular sheath is configuredto be received by the introducer sheath during insertion of the catheterinto the introducer sheath such that the tubular sheath remainssubstantially stationary relative to the introducer sheath while slidingproximally relative to the catheter as the catheter is inserted distallyat least until the expandable balloon is fully inserted into theintroducer sheath without substantial contact between the tubular sheathand the expandable balloon.

In a twenty-fourth example, aspects of the disclosure relate to a methodof inserting expandable balloons that includes locating a distal portionof a catheter of a medical device immediately proximal to an introducersheath inserted in a patient. The medical device includes an expandableballoon that is attached to the distal portion of the catheter and atubular sheath configured to enclose the expandable balloon, wherein agripping portion of the tubular sheath has relatively poor cohesivestrength to adjacent portions of the tubular sheath such that thetubular sheath is configured to be split along the gripping portion toenable the tubular sheath to be splittably removable from the catheter.The gripping portion of the tubular sheath extends from a proximal endof the tubular sheath to a distal end of the tubular sheath and extendsthrough a thickness of a wall of the tubular sheath. The method ofinserting expandable balloons also includes distally pushing thecatheter into the introducer sheath such that the tubular sheath remainsstationary relative to the introducer sheath while sliding proximallyrelative to the catheter as the catheter is inserted distally at leastuntil the expandable balloon is fully inserted into the introducersheath without substantial contact between the tubular sheath and theexpandable balloon. The method of inserting expandable balloons alsoincludes splitting the tubular sheath using the gripping portion toremove the tubular sheath from the catheter in response to fullyinserting the expandable balloon into the introducer sheath.

In a twenty-fifth example, aspects of the disclosure relate to a methodof inserting expandable balloons that includes locating a distal portionof a catheter of a medical device immediately proximal to an introducerinserted in a patient. The medical device includes an expandable balloonthat is attached to the distal portion of the catheter and a tubularsheath configured to enclose the expandable balloon, where the tubularsheath includes at least one longitudinal splitting element within awall of the tubular sheath. The at least one longitudinal splittingelement is configured to split the wall of the tubular sheath inresponse to a force greater than a threshold force upon the at least onelongitudinal splitting element and also extends from a proximal end ofthe tubular sheath to a distal end of the tubular sheath. The method ofinserting expandable balloons also includes distally pushing thecatheter into the introducer sheath such that the tubular sheath remainsstationary relative to the introducer sheath while the tubular sheathslides proximally relative to the catheter as the catheter is inserteddistally at least until the expandable balloon is fully inserted intothe introducer sheath without substantial contact between the tubularsheath and the expandable balloon. The method of inserting expandableballoons also includes splitting the tubular sheath using the at leastone longitudinal splitting element to remove the tubular sheath from thecatheter in response to fully inserting the expandable balloon into theintroducer sheath.

The details of one or more examples are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a conceptual and schematic diagram illustrating a view of anexample medical device including an example tubular sheath enclosing anexample expandable balloon on an example catheter near an exampleintroducer sheath inserted in a body of a patient.

FIGS. 1B-1D are conceptual and schematic views of the medical device ofFIG. 1A, including a cross-sectional view of the catheter of FIG. 1A(FIG. 1B), a view of the expandable balloon on the catheter without thetubular sheath of FIG. 1A (FIG. 1C), and the tubular sheath of FIG. 1A(FIG. 1D).

FIGS. 2A-2D are conceptual and schematic diagrams illustrating a sideview of an example tubular sheath with a longitudinal splitting element(FIG. 2A), a side view of an example tubular sheath with a spirallyconfigured splitting element (FIG. 2B), a cross-sectional view takenalong cross-sectional cut plane 174 in FIG. 2A (FIG. 2C), and a sideview of an example tubular sheath in a split configuration (FIG. 2D).

FIGS. 3A and 3B are conceptual and schematic diagrams illustrating aside view of a tubular sheath with a first example longitudinalsplitting element (FIG. 3A) and a cross-sectional view of the tubularsheath of FIG. 3A taken along cross-sectional cut plane 228 (FIG. 3B).

FIGS. 4A and 4B are conceptual and schematic diagrams illustrating aside view of a tubular sheath with a second example longitudinalsplitting element (FIG. 4A), and a cross-sectional view of the tubularsheath of FIG. 4A taken along the cross-sectional cut plane 248 (FIG.4B).

FIGS. 5A-5C are conceptual and schematic diagrams illustrating a sideview of another example tubular sheath with a first example grippingportion in the enclosing configuration (FIG. 5A), a cross-sectional viewof the tubular sheath of FIG. 5A taken along cross-sectional cut plane374 (FIG. 5B), and a side view of the tubular sheath of FIG. 5A in asplit configuration (FIG. 5C).

FIGS. 6A and 6B are conceptual and schematic diagrams illustrating aside view of a tubular sheath with a second example gripping portion(FIG. 6A) and a cross-sectional view of the tubular sheath of FIG. 6Ataken along cross-sectional cut plane 426 (FIG. 6B).

FIGS. 7A and 7B are conceptual and schematic diagrams illustrating aside view of a tubular sheath with a third example gripping portion(FIG. 7A) and a cross-sectional view of the tubular sheath of FIG. 7Ataken along cross-sectional cut plane 444 (FIG. 7B).

FIG. 8 is a flow diagram illustrating an example method of inserting anexpandable balloon into a patient using a tubular sheath of the presentdisclosure.

FIGS. 9A-9C are conceptual and schematic diagrams illustrating anexample tubular sheath of the present disclosure being insertedaccording to the flow diagram of FIG. 8, including the example tubularsheath of the present disclosure being located proximal to an exampleintroducer sheath (FIG. 9A), being pushed proximally by the exampleintroducer sheath (FIG. 9B), and being split open on the examplecatheter (FIG. 9C), respectively.

DETAILED DESCRIPTION

In general, the disclosure describes an example medical device thatincludes a tubular sheath that encloses an expandable balloon on thedistal portion of a catheter. The medical device may be used, in part,to enclose an expandable balloon during packaging, storing, andinserting of the expandable balloon into a body of a patient. Thetubular sheath is configured to split open. The tubular sheath mayinclude a longitudinal splitting element, a gripping portion tofacilitate splitting the tubular sheath, or both.

Expandable medical balloons are used in a variety of medical procedures,such as angioplasty, tuboplasty, or pyeloplasty. In medical procedures,the expandable balloon may be attached to a catheter that is configuredto be manipulated to navigate the expandable balloon to a target site.The target site may be a location within a patient's body where anailment of the patient's body is treated. In some medical procedures,the expandable balloon may be navigated to the target site in anunexpanded (deflated) state and then expanded (inflated) at the targetsite as part of the medical procedure.

The expandable balloon may be relatively delicate, being prone tokinking or flexing in ways that damage the structural integrity of theexpandable balloon. For example, if handled improperly, the expandableballoon may become stuck to itself or become stretched, such that uponbeing inflated, the expandable balloon may not inflate evenly or in theintended shape, or may inflate with an undesired weakness (e.g., theweakness making the expandable balloon more susceptible topopping/breaking). Additionally, the catheter to which the expandableballoon is attached may be relatively delicate, such that prolonged orforceful manipulation may result in a portion of the catheter bucklingor breaking. For example, in response to a clinician having difficultyinserting an expandable balloon into a patient (e.g., where a clinicianhas a difficult angle of entry or is having difficulty fitting theexpandable balloon into an introducer sheath as described herein), thecatheter may be prone to buckling or breaking at a location proximal tothe point of insertion. In some examples, the expandable balloon may bedamaged as described above in response to the catheter buckling orbreaking, such that it is difficult or impossible to utilize the damagedexpandable balloon. In other examples, the catheter itself may bedifficult or impossible to use upon buckling or breaking, such that itmay be difficult or impossible to insert and therein utilize theexpandable balloon while the expandable balloon is attached to thedamaged catheter.

The tubular sheaths described herein may enclose and protect or shieldthe expandable balloon until it is no longer possible/practicable toenclose the expandable balloon (e.g., upon inserting the expandableballoon into an introducer sheath inserted in a patient). By enclosingthe expandable balloon substantially through insertion, the tubularsheath may facilitate insertion of the expandable balloon, thus reducingthe likelihood of buckling or otherwise damaging the catheter as aresult of a difficult insertion. Further, enclosing the expandableballoon in a tubular sheath described herein may reduce or substantiallyeliminate contact between the expandable balloon and a user such as aclinician that is manipulating the expandable balloon or catheter.Providing this tubular support for the expandable balloon and catheterduring operation (e.g., insertion into the patient's anatomy such asperipheral arteries) may reduce the likelihood of kinking or flexing theexpandable balloon. Additionally, the tubular sheath may be configuredto slide along the catheter, such that during insertion the tubularsheath may stay proximal to an introducer sheath while the expandableballoon and catheter slide distally through tubular sheath. Byconfiguring the tubular sheath to slide along the catheter, the tubularsheath may provide support to the most vulnerable portion of thecatheter (e.g., the portion of the catheter immediately proximal to thepoint of insertion), thus reducing the likelihood of the catheterbuckling or otherwise becoming damaged during insertion.

Further, in some expandable balloons, an external surface of theexpandable balloon may be coated with a drug, which is delivered to thetarget site upon expanding the expandable balloon. For example, the drugmay be intended to stop a hyperproliferative response of an intimawithin the vasculature of a patient. Such drug coatings may haverelatively low adhesion to the expandable balloon such that contactbetween the drug coating and other surfaces or structures may removesome drug coating from the external surface of the expandable balloon.This may increase variability and/or unpredictability in an amount ofdrug delivered to the target site, both of which are undesirable. Thetubular sheaths described herein may reduce inadvertent removal of drugfrom the surface of a coated expandable balloon (e.g., due to contactwith a user such as a clinician that is manipulating the balloon orcatheter). One advantage of the tubular sheaths described here is thatthey can each be removed relatively easily without damaging theexpandable balloon or any coating while providing tubular support forboth the expandable balloon and the catheter during insertion into thepatient's anatomy (e.g., peripheral arteries). Further, the tubularsheath may reduce the likelihood of drug transfer to a clinicianhandling the expandable balloon by enclosing the drug coatingsubstantially through insertion of the expandable balloon into apatient.

In some examples, tubular sheaths described herein may include one orrelatively few components rather than multiple components. Configuring atubular sheath such that the tubular sheath is made from one orrelatively few components may reduce the difficulty of manufacturing,assembling, and/or using the tubular sheaths. In some examples, theappearance and dimensions of the tubular sheaths described herein may besubstantially similar or identical to other non-splittable and/ornon-slidable sheaths, which may enable a clinician to recognize and morequickly understand the nature and operability of the tubular sheaths.Additionally, by configuring the tubular sheaths described herein to belike other non-splittable and/or non-slidable sheaths, the tubularsheaths described herein may be relatively easier to integrate intoexisting manufacturing processes or treatment procedures (e.g., tubularsheaths may be configured to utilize existing packaging and definedimensional fits with expandable balloons according to existingmanufacturing procedures).

FIG. 1A is a conceptual and schematic diagram illustrating a view of anexample medical device 10 including an example tubular sheath 12 that isenclosing an expandable balloon 14 that is attached to a catheter 16.The expandable balloon 14 may be attached to the catheter 16 adjacent toa distal portion 18 of the catheter 16. In some examples, the expandableballoon 14 is fixedly attached adjacent to the distal portion 18 of thecatheter 16, such that it is difficult or impossible to remove theexpandable balloon 14 from the catheter 16 without damaging one or bothof the expandable balloon 14 or the catheter 16. In other examples, theexpandable balloon 14 is loosely or removably attached to the catheter16, such that the expandable balloon 14 may be detached from thecatheter 16 once the expandable balloon 14 is navigated to the targetsite.

In some examples, the system in which the medical device 10 is utilizedmay include an introducer sheath 22. The introducer sheath 22 may beinserted into the patient transcutaneously in order to access avasculature 24 of a patient 26. In some examples, the introducer sheath22 may include external threads 23, which may be configured to mate withcomplementary threads defined in the tubular sheath 12. In otherexamples, the introducer sheath 22 may omit the external threads 23. Aninternal diameter of the introducer sheath 22 may be selected toaccommodate an external diameter of the expandable balloon 14 (e.g., ina deflated state) and an external diameter of the catheter 16.Alternatively, some or all of the internal diameter of the introducersheath 22 may be selected to accommodate an external diameter of thetubular sheath 12 in examples where the tubular sheath 12 is configuredto be inserted into the introducer sheath 22. For example, aproximal-most internal diameter of the introducer sheath 22 may beselected to accommodate external diameters of the catheter 16, theexpandable balloon 14, and the tubular sheath 12, while a relativelydistal internal diameter of the introducer sheath 22 is selected toaccommodate an external diameter of the catheter 16 and the expandableballoon 14 and not the tubular sheath 12. In such an example, thetubular sheath 12 may be inserted past the initial external diameter ofthe introducer sheath 22 and then be received (e.g., stopped) by thesecondary internal diameter of the introducer sheath 22, while theexpandable balloon 14 and catheter 16 are dimensioned to distally movethrough the entirety of the introducer sheath 22.

The vasculature 24 of the patient 26 into which the introducer sheath 22is inserted may be selected to provide access to a selected target siteto which the expandable balloon 14 will be advanced. For example, theexpandable balloon 14 may be used to provide anti-restenotic therapy toa target site in peripheral vasculature of a patient 26.

The catheter 16 extends from a proximal portion 36 adjacent to a hub 38,such as a manifold, to the distal portion 18. The expandable balloon 14is connected to the distal portion 18 of the catheter 16. The catheter16 may include structural features that enable expansion or inflation ofthe expandable balloon 14 and advancing of the expandable balloon 14 tothe target site in the patient 26. For example, the catheter 16 mayinclude a guidewire lumen 42 and an inflation lumen 44, as shown in FIG.1B.

FIG. 1B is a cross-sectional view of the catheter 16 taken along thecross-sectional cut plane 40 in FIG. 1A. The guidewire lumen 42 may beconfigured to receive a guidewire 20. In some examples, the guidewirelumen 42 may extend longitudinally through the catheter 16 from thedistal portion 18 to the hub 38. The hub 38 may include a first portthat provides access to the guidewire lumen 42 to facilitate advancingthe catheter 16 along the guidewire 20. Similarly, the inflation lumen44 may extend longitudinally through the catheter 16 from the hub 38 tothe expandable balloon 14. The hub 38 may include a second port thatprovides access to the inflation lumen 44. The inflation lumen 44 mayterminate distally at an orifice to the interior of the expandableballoon 14. The inflation lumen 44 may be configured to receive a fluidthat is flowed into the inflation lumen 44 from the hub 38 to expand orinflate the expandable balloon 14 (e.g., once the expandable balloon 14has been navigated to the target site).

FIG. 1C is a conceptual and schematic diagram illustrating a side viewof the expandable balloon 14 as arranged on the catheter 16 without thetubular sheath 12. As depicted in FIG. 1C, the expandable balloon 14 isin a deflated configuration 46, which includes the expandable balloon 14being folded or “pleated” into a physically smaller profile than theprofile of the expandable balloon 14 in an inflated configuration. It isto be understood that the general shape of the deflated configuration 46in FIG. 1C is for illustration purposes only; other shapes andconfigurations of the expandable balloon 14 in a non-inflated (e.g.,deflated) configuration 46 are also possible. Further, as depicted inFIG. 1C, the guidewire 20 extends from a position distal to theexpandable balloon 14 longitudinally through the catheter 16 to the hub38. In some examples, the guidewire 20 may be advanced through thevasculature 24 of a patient 26 during a previous step, such that thecatheter 16 is advanced over the guidewire 20 using the guidewire lumen42 to navigate the expandable balloon 14 to the target site (e.g., usingthe Seldinger technique). During such a technique, the guidewire 20 mayonly extend as far proximally through the guidewire lumen 42 as thecatheter 16 has been pushed distally along the guidewire 20.

The expandable balloon 14 may be formed from any suitable material thatprovides sufficient strength and flexibility for the pressuresexperienced by the expandable balloon 14 during the inflation procedure.The materials from which the expandable balloon 14 is formed may bebiocompatible and compatible with a drug coating on the external surface48 of the expandable balloon 14. In some examples, materials from whichthe expandable balloon 14 is formed may include nylon, polyethyleneterephthalate (PET), polyethylene (such as crosslinked polyethylene),polyurethane, polyvinyl chloride, silicone elastomer, or the like.

In some examples, the expandable balloon 14 may include a coating on anexternal surface 48 of the expandable balloon. The coating may include,for example, a lubricious coating (either hydrophilic or hydrophobic), adrug coating, or the like. In some examples, the drug coating mayinclude a drug selected to treat peripheral artery disease, such as ananti-restenotic or anti-proliferative drug. An exampleanti-proliferative drug is paclitaxel. In some examples, the drugcoating may further include an excipient to facilitate release of thedrug from the drug coating. Example excipients include urea,polysorbate, sorbitol, or the like.

FIG. 1D is a conceptual and schematic diagram illustrating a side viewof the tubular sheath 12. The tubular sheath 12 may be made of any of anumber of suitable materials, such as poly(tetrafluoroethylene) (PTFE),high density polyethylene (HDPE), or low density polyethylene (LDPE).The tubular sheath 12 is configured to enclose the expandable balloon 14until the expandable balloon is inserted into the vasculature 24 of apatient 26 and/or inserted into an introducer sheath 22 inserted withinthe vasculature 24 of a patient 26. Configuring the tubular sheath 12 toenclose the expandable balloon 14 through the process of insertion mayreduce the necessity or possibility of manual handling of the expandableballoon 14. Reducing the possibility or necessity of manual handling ofthe expandable balloon 14 may result in structural or pharmaceuticalbenefits for the medical device 10, as manually handling the expandableballoon 14 may physically damage the expandable balloon 14, the shaft ofthe catheter 16, or both, unnecessarily remove any drug coating from theexpandable balloon 14, or both.

As discussed herein, the tubular sheath 12 is configured to be slidablealong the catheter and splittably removable from the catheter 16. Thetubular sheath 12 may be removed in conjunction with the expandableballoon 14 being inserted into the body of a patient 26. In someexamples, the tubular sheath 12 may be removed from the catheter 16 as aresult of a sufficient force being applied to a gripping portion thathas relatively poor cohesive strength to adjacent portions of thetubular sheath 12. In other examples, the tubular sheath 12 may beremoved from the catheter 16 as a result of a sufficient force beingapplied to one or more longitudinal splitting elements within a wall ofthe tubular sheath that are configured to split the tubular sheath 12.The force may be applied by a user, such as a clinician. A sufficientforce may be a force above a threshold amount of force. The thresholdamount of force should be selected to be sufficiently low to enable auser such as a clinician to split the tubular sheath 12 and sufficientlyhigh to reduce inadvertent splitting of the tubular sheath, for example,due to inadvertent catching of the tubular sheath on another structureduring manufacturing, storage, shipping, or handling prior to thetreatment procedure.

The tubular sheath 12 is configured to enclose the expandable balloon14. For example, the tubular sheath 12 may be configured to enclose theexpandable balloon 14 during storage, handling, and at least an initialportion of a treatment procedure. The tubular sheath 12 may beconfigured to support the expandable balloon 14, catheter 16, or bothduring the insertion of the expandable balloon 14 (e.g., insertion intothe introducer sheath 22) to reduce or substantially eliminate bendingand kinking of the expandable balloon 14, catheter 16, or both duringinsertion into the introducer sheath 22. In some examples, the tubularsheath 12 may be sized relative to the expandable balloon 14 so thatcontact between the expandable balloon 14 and the tubular sheath 12 isreduced or minimized. For example, an internal diameter 28 of thetubular sheath 12 may be greater than an external diameter 30 of theexpandable balloon 14 when the expandable balloon 14 is in the deflatedconfiguration 46. Further, a longitudinal length 32 of the tubularsheath 12 may be greater than a longitudinal length 34 of the expandableballoon 14. For example, the tubular sheath 12 may be at least 300millimeters long (e.g., as such a length may cover many varieties ofexpandable balloons 14). Configuring the tubular sheath 12 tosubstantially cover the expandable balloon 14 while reducing orminimizing contact between the tubular sheath 12 and the expandableballoon 14 may increase the physical integrity of both the expandableballoon 14 and any drug coating on the expandable balloon 14, as contactmay result in either or both a portion of the drug coating beingpartially removed and one or more of the expandable balloon 14 and/orcatheter 16 kinking.

The tubular sheath 12 may be configured to define a relatively reducedprofile, such that an outer diameter 35 of the tubular sheath 12 isnearly equal to an external diameter 30 of the deflated state of theexpandable balloon 14 (e.g., the tubular sheath 12 may define anexternal diameter 30 that is less than two times the external diameter30 of the deflated state of the expandable balloon 14). In someexamples, the outer surface of the tubular sheath 12 may define agenerally continuous and tubular outer surface (e.g., an outer surfacethat does not define large ridges or lips that double or triple adiameter of the tubular sheath 12). Put differently, a longitudinalprofile of the tubular sheath 12 may be configured to avoid extendingout radially from the relative shape of the expandable balloon 14 morethan what facilitates moving the tubular sheath 12 on the catheter 16 asdescribed herein. For example, other than a proximal flare 50 and distalflare 52 as discussed below with respect to FIG. 1D, tubular sheath 12may omit features that substantially extend radially outward (e.g.,extend outward to more than two or three times an internal diameter 28of the tubular sheath 12).

The expandable balloon 14 may be stored and shipped attached to thecatheter 16 within a channel or lumen of a container, where removing theexpandable balloon 14 and catheter 16 from the container may include aclinician longitudinally extracting the catheter 16 (and the expandableballoon 14) through the channel or lumen. In examples in which aclinician removes the medical device 10 from a container bylongitudinally traversing the medical device 10 through a channel orlumen, the channel or lumen of a container must be at least as large asthe greatest radius as the medical device 10 that the container willstore. Thus, reducing the longitudinal profile of the tubular sheath 12may reduce a size of the container used to store the medical device 10.

The tubular sheath 12 may be configured to generally maintain a stableposition on the catheter 16 relative to the catheter 16 as the catheter16 is handled. For example, the tubular sheath 12 may be configured tomaintain a position over the expandable balloon 14 such that the tubularsheath 12 substantially always houses the expandable balloon 14 as thecatheter 16 is handled/moved by a clinician (e.g., whether or not theclinician is specifically handling/holding the tubular sheath 12 inplace) until insertion of the expandable balloon 14 into the introducersheath 22. In some examples, the tubular sheath 12 is configured to bemoved relative to the catheter 16 (e.g., subsequent to a retainingmember exposing the expandable balloon 14 as described herein) inresponse to the clinician applying more than a threshold force upon thetubular sheath 12 and/or a retaining member as described herein, wherethe threshold force is more than a nominal force (e.g., gravity orincidental contact as a result of the tubular sheath 12 unintentionallyor otherwise minimally contacts an object). The tubular sheath 12 may beconfigured to maintain a relatively stable position on the catheter 16because of a fit of the tubular sheath 12 on the expandable balloon 14(e.g., a friction fit). Configuring the tubular sheath 12 to generallymaintain a stable position on the catheter 16 relative to the catheter16 while a clinician is handling the medical device 10, whether or notthe tubular sheath 12 is purposefully externally supported (e.g.,supported by the clinician) during such handling, may improve an abilityof the tubular sheath 12 to house and protect the expandable balloon 14,catheter 16, or both during handling and insertion of the expandableballoon 14 and the catheter 16 into introducer sheath 22

In some examples, the tubular sheath 12 is configured to slideproximally relative to the catheter 16 as the catheter 16 is pusheddistally into the introducer sheath 22. In certain examples, the tubularsheath 12 may be further configured to structurally support theexpandable balloon 14, catheter 16, or both during insertion (e.g., tohelp one or both of the expandable balloon 14 or catheter 16 avoidkinking or bending). For example, the tubular sheath 12 may create aLuer connection with the introducer sheath 22 (e.g., using externalthreads 23 on the introducer sheath 22) to provide additional support toone or both of the expandable balloon 14 or catheter 16 duringinsertion. By being configured to slide proximally relative to thecatheter 16 while supporting the expandable balloon 14, catheter 16, orboth as a clinician feeds the catheter 16 into the introducer sheath 22,the tubular sheath 12 protects the expandable balloon 14 until theexpandable balloon 14 is substantially fully inserted into theintroducer sheath 22. This may reduce or substantially eliminate manualhandling of the expandable balloon 14 by a user such as a clinician,which may result in structural or pharmaceutical benefits for themedical device 10. For example, manually handling the expandable balloon14 may increase the risk of physically damaging one or both of theexpandable balloon 14 or catheter 16 or unnecessarily removing drugcoating from the expandable balloon 14, such that avoiding manuallyhandling the expandable balloon 14 is advantageous.

Further, configuring the tubular sheath 12 to be both removable andslidable on the catheter 16 may increase the operational length of thecatheter 16 during a medical procedure. For example, if a tubular sheath12 was slidable but not removable, in response to the tubular sheath 12being slid proximally back to a proximal portion 36 of the catheter, alength of the catheter 16 that is equal or greater to the length 32 ofthe tubular sheath 12 may be operationally unusable (e.g., as thetubular sheath 12 may be neither able to slide proximally over the hub38 of the catheter 16 nor able to be inserted into the introducer sheath22). In some examples, it may be advantageous to delay removing thetubular sheath 12 from the catheter 16 until the expandable balloon 14is distally past the introducer sheath 22 into the vasculature 24 of thepatient 26, as the act of insertion may be complicated and prone forerror (such that minimizing the steps thereof is useful in reducing thelikelihood of error) in comparison to the act of vasculature 24navigation.

As depicted in FIG. 1D, in some examples, the tubular sheath 12 may beconfigured with a proximal flare 50 and distal flare 52, such that aproximal end 64 and distal end 66 of the tubular sheath 12 may flareoutward from a middle section of the tubular sheath 12. The proximalflare 50 may be configured to facilitate proximal sliding of the tubularsheath 12 over a catheter 16. The distal flare 52 may be configured tofacilitate distal sliding of the tubular sheath 12 over the expandableballoon 14, forming a contact fit with the insertion sheath 22, or thelike. In other examples (not depicted), the distal flare 52 may flare toa different final diameter or may flare at a different angle relative tothe proximal flare 50. In certain examples, the tubular sheath 12 mayhave a proximal flare 50 but not a distal flare 52, or vice versa, or noflare at all.

As discussed herein, the tubular sheath 12 is configured to split inresponse to application of a force above a threshold force to astructural feature of the tubular sheath 12, such as a longitudinalsplitting element or a gripping element. Several different examplemechanisms for splitting the tubular sheath 12 are discussed within thisdisclosure. For example, the tubular sheath may include a plurality oflongitudinal perforations or a longitudinal slit or cut, any of whichmay be configured to make the tubular sheath 12 splittable. Each slit,cut, or perforation may cut substantially through one side of thetubular sheath 12. The slit, cut, or plurality of perforations mayextend from a proximal end 64 of the tubular sheath 12 to a distal end66 of the tubular sheath 12. While in some examples the slit, cut, orperforations may be substantially parallel with a longitudinal axis 62of the tubular sheath 12, in other examples the slit, cut, orperforations may be at an angle relative to the longitudinal axis 62 ofthe tubular sheath 12 or may spiral around the longitudinal axis 62 ofthe tubular sheath 12. Further, while in some examples the tubularsheath 12 may include a single slit, cut, or line of perforations, inother examples, the tubular sheath 12 may include two or more slits,cuts, or lines of perforations extending along the tubular sheath 12.Other mechanisms for splitting tubular sheaths 12 may include a wireembedded in a wall of a tubular sheath 12, longitudinal holes within awall of a tubular sheath 12, longitudinal grooves along a wall of atubular sheath 12, a pair of longitudinal perforations defining agripping portion of a tubular sheath 12, or a longitudinal subsection ofthe tubular sheath 12 that has relatively poor cohesive strength toadjacent portions of the tubular sheath 12 to define a gripping section,each of which are described in further detail below.

FIGS. 2A-2D are conceptual and schematic diagrams illustrating anexample tubular sheath 112 having a longitudinal splitting element 160in various configurations. The tubular sheath 112 may be substantiallysimilar to the tubular sheath 12 of FIG. 1A, aside from the differencesdescribed herein. As depicted in FIG. 2A, the tubular sheath 112 mayhave a relatively consistent profile between a proximal end 164 anddistal end 166 of the tubular sheath 112. For example, the tubularsheath 112 may have a relatively consistent radius 172 throughout thetubular sheath 112. In other examples, the tubular sheath 112 may definea number of distinct profiles or have a varying profile between theproximal end 164 and distal end 166 of the tubular sheath 112, so longas the tubular sheath 112 is configured to substantially enclose theexpandable balloon 14 while reducing contact with the expandable balloon14.

The tubular sheath 112 may include a longitudinal splitting element 160.The longitudinal splitting element 160 may be a feature of the tubularsheath 112 that is within a wall of the tubular sheath 112 and isconfigured to split the tubular sheath 112. The longitudinal splittingelement 160 may extend along a longitudinal axis 162 of the tubularsheath 112. The splitting element 160 may extend from a proximal end 164of the tubular sheath 112 to a distal end 166 of the tubular sheath 112.The splitting element 160 may define two sides 168, 170 of the tubularsheath 112 on either side of the splitting element 160. The splittingelement 160 may be configured to split the tubular sheath 112 betweenthe two sides 168, 170 in response to a force above a threshold forcebeing applied to the splitting element 160 or to the two sides 168 and170 in opposite directions. The longitudinal splitting element 160 mayinclude, for example, a wire embedded in a wall 184 (FIG. 2C) of thetubular sheath 112, a plurality of longitudinal perforations formed inthe wall 184 of the tubular sheath 112, a combination of a wire embeddedin the wall 184 with perforations formed in the wall 184 adjacent to thewire, or the like.

In some examples, the splitting element 160 may be substantiallyparallel with the longitudinal axis 162. In other examples, thesplitting element 160 may be at a fixed or varying angle relative to thelongitudinal axis 162 as the splitting element 160 extends between theproximal end 164 and distal end 166 of the tubular sheath 112. Forexample, as depicted in FIG. 2B, the splitting element 160 may spiralone or more times around the longitudinal axis 162 on the tubular sheath112 between the proximal end 164 and distal end 166 of the tubularsheath 112. Though the tubular sheath 112 only includes one splittingelement 160 as depicted in FIGS. 2A-2C for purposes of clarity, in someexamples the tubular sheath 112 may include two or more longitudinalsplitting elements 160 at two or more locations around the tubularsheath 112.

In some examples, the inner wall 188 adjacent to the distal end 166 ofthe tubular sheath 112 may be internally threaded with threads 182. Thethreads 182 may act as a Luer connector to enable the tubular sheath 112to connect to an introducer sheath 122. Configuring the inner wall 188adjacent to the distal end 166 of the tubular sheath 112 to definethreads 182 to configure the distal end 166 of the tubular sheath 112 tobe a Luer connector may enable the tubular sheath 112 to introduce anexpandable balloon 14 to the introducer sheath 122 in a more stablemanner. Configuring tubular sheaths 112 to improve the stability of theinsertion of expandable balloon 14 may decrease risk of causing physicaldamage or contact to the expandable balloon 14.

FIG. 2C is a conceptual and schematic diagram illustrating across-sectional view along the longitudinal axis 162 of the tubularsheath 112 from the cross-sectional cut plane 174. As depicted in FIG.2C, the splitting element 160 is within a wall 184 of the tubular sheath112. In some examples, the splitting element 160 may be entirely betweenan outer wall 186 of the tubular sheath 112 and an inner wall 188 of thetubular sheath 112. In other examples (not depicted), the splittingelement 160 may extend radially in-line with or beyond the outer wall186 of the tubular sheath 112 (e.g., such that the splitting element 160partially extends radially beyond a portion of the outer wall 186). Insome examples, the tubular sheath 112 may include a space 190 betweenthe splitting element 160 and the inner wall 188 (e.g., such that thesplitting element 160 is always at least a minimum radial distance awayfrom the inner wall 188). As a result of the tubular sheath 112 definingthe splitting element 160 to always have a space 190 between itself andthe inner wall 188, the inner wall 188 may include a relatively smoothlongitudinal cross-section, potentially reducing the possibility that anexpandable balloon 14 enclosed within the tubular sheath 112 may bedamaged by, for example, an internal edge, protrusion, or divot in theinner wall 188.

In some examples, the inner wall 188 may be lubricious to reducefriction between the inner wall 188 and the expandable balloon 14. Insome examples, the inner wall 188 may include a lubricious coating, suchas a hydrophilic coating, a PTFE coating, a HDPE coating, or the like.For example, the majority of the tubular sheath 112 may be made of LDPE,while the inner wall 188 is coated with a hydrophilic coating, PTFE, orHDPE. Alternatively, the entirety of the tubular sheath 112 may be madeof a lubricious material, such as PTFE, HDPE, or the like. Configuringthe inner wall 188 of the tubular sheath 112 to be lubricious may reducethe likelihood of the tubular sheath 112 physically damaging an enclosedexpandable balloon 14 or removing some of the drug coating on anexternal surface 48 of an enclosed expandable balloon 14.

The inner wall 188 of the tubular sheath 112 defines an inner lumen 192of the tubular sheath 112. The inner lumen 192 is configured to enclosethe expandable balloon 14. In some examples, cross-sectional dimensionsof the inner lumen 192 may be substantially constant along thelongitudinal axis 162 of the tubular sheath 112. In other examples,cross-sectional dimensions of the inner lumen 192 as measured along thelongitudinal axis 162 of the tubular sheath 112 may vary along a lengthof the tubular sheath 112.

Though the tubular sheath 112 is discussed and depicted throughout thisdisclosure as tubular in shape for purposes of clarity and illustration,it is to be understood that many substantially tubular shapes are withinthe scope of this disclosure. For example, the tubular sheath 112 maydefine a changing radius 172 along the longitudinal axis 162 of thetubular sheath 112. Additionally or alternatively, the cross-section ofthe tubular sheath 112 may be, for example, oblong, egg, ordiamond-shaped through a portion or the entirety of the length of thetubular sheath 112.

The tubular sheath 112 may be in an enclosing configuration 194 whileenclosing the expandable balloon 14 on the catheter 16. The longitudinalsplitting element 160 is configured to split open the tubular sheath 112into a split configuration, such as the split configuration 196 of FIG.2D. For example, the longitudinal splitting element 160 may include awire embedded in a wall of the tubular sheath 112 (e.g., similar to thewire 220 in tubular sheath 212A of FIGS. 3A and 3B), such that applyinga force to the wire splits the tubular sheath 112 open. For anotherexample, the longitudinal splitting element 160 may include holes and/orgrooves that extend through the tubular sheath 112 (e.g., similar toholes 240A-D and grooves 242A-B of tubular sheath 212B of FIGS. 4A and4B) that structurally weaken the tubular sheath 112, such that a forceapplied to the holes and/or grooves may result in the tubular sheath 112splitting along an axis aligned with the holes and/or grooves. Whensplit using the splitting element 160, the tubular sheath 112 may splitinto the two sides 168, 170 of the tubular sheath 112. The splitconfiguration 196 exposes the inner lumen 192 such that the tubularsheath 112 may be removed from the catheter 16. The tubular sheath 112may be configured to stay in the enclosing configuration 194 while theexpandable balloon 14 is being inserted into the vasculature 24 of apatient 26, as discussed in more detail below.

FIGS. 3A-4B relate to examples of longitudinal splitting elements 160within example tubular sheaths 212A and 212B (collectively, “tubularsheaths 212”). For example, FIG. 3A is a conceptual and schematicdiagram illustrating a side view of an example tubular sheath 212A thatincludes a longitudinal splitting element 160 including a wire 220. Thetubular sheaths 212 may be substantially similar to the tubular sheaths12 and 112 of FIGS. 1A-2D aside from the differences described herein.For example, the tubular sheaths 212 are not depicted as including aproximal flare 50 or a distal flare 52 for purposes of clarity. In otherexamples, the tubular sheaths 212 may include both a proximal flare 50and distal flare 52 as in tubular sheath 12, or the tubular sheaths 212may have only a proximal flare 50 or only a distal flare 52, or no flareat all. In some examples, the tubular sheath 212 may be relativelyeasier to split as a result of not including a proximal flare 50 ordistal flare 52 (e.g., as a result of a splitting force applied by aphysician not having to change angles or directions when applied alongthe tubular sheath 212). The wire 220 is embedded within a wall 284 ofthe tubular sheath 212A. The wire 220 may be embedded within the wall284 substantially similarly to how the longitudinal splitting element160 was within the wall 184 of the tubular sheath 112.

As depicted in FIG. 3A, the wire 220 may extend substantially parallelwith a longitudinal axis 262 of the tubular sheath 212A. A proximal end222 of the wire 220 may extend proximally from the proximal end 264 ofthe tubular sheath 212A. Further, a distal end 224 of the wire 220 mayextend distally from the distal end 266 of the tubular sheath 212A. Insome examples, only one of the proximal end 222 or distal end 224 mayextend proximally or distally from respective ends of the tubular sheath212A, respectively. Configuring the wire 220 to extend from the proximalend 264, distal end 266, or both, of the tubular sheath 212A enables aclinician to apply a force to the wire 220. Tabs 226A-226B(collectively, “tabs 226”) may be stably affixed to the proximal end 222and distal end 224 of the wire 220. The tabs 226 may further facilitatethe application of force. In some examples, rather than including bothof the tabs 226, the tubular sheath 212A may include only the first tab226A or only the second tab 226B.

The wire 220 is configured to split the tubular sheath 212A in responseto a force above a threshold force being exerted upon the wire 220(e.g., by a user such as a clinician). To facilitate splitting thetubular sheath 212A, the wire 220 has a substantially higher tensilestrength than the tubular sheath 212A through which the wire 220 ispulled. The threshold force may be a force that is higher than a nominalforce that may be unintentionally exerted upon the wire 220 while alsobeing less than a maximum force that an adult could exert upon the wire220. Put differently, the threshold force may be a force that isrelatively easy for an adult to intentionally apply to the wire 220while simultaneously being relatively difficult to unintentionally applywhile handling the medical device 10. In some examples, the force may beexerted upon a proximal end 222 or distal end 224 of the wire 220, orexerted upon one of the tabs 226 connected to either end 222, 224 of thewire 220.

Though FIG. 3A depicts a single wire 220 running substantially parallelto the longitudinal axis 262 of the tubular sheath 212A, in otherexamples, the tubular sheath 212A may include two or more wires 220,each of which may be extending parallel with or at an angle to thelongitudinal axis 262 of the tubular sheath 212A. For example, thetubular sheath 212A may include a wire 220 that extends through the wall284 of the sheath in a spiral about the longitudinal axis 262 (e.g.,similar to FIG. 2B).

FIG. 3B is a conceptual and schematic diagram illustrating across-sectional view of the tubular sheath 212A and wire 220 of FIG. 3Aas viewed facing the cross-sectional cut plane 228. In some examples,the wire 220 may occupy a majority of a cross-sectional thickness 232 ofthe wall 284 of the tubular sheath 212. For example, a diameter 230 ofthe wire 220 may be at least 50% of a cross-sectional thickness 232 ofthe wall 284 of the tubular sheath 212A. In other examples, the wire 220may be larger (e.g., 75% of the cross-sectional thickness 232) orsmaller (e.g., 25% of the cross-sectional thickness 232). Configuringthe wire 220 to have a larger diameter may decrease the threshold forceneeded for a clinician to split the tubular sheath 212A.

Thus, when the tubular sheath 212A is on the expandable balloon 14, thetubular sheath 212A encloses the expandable balloon 14, but once theexpandable balloon 14 is inserted into the introducer sheath 22 (FIG.1A), the wire 220 may be pulled by a clinician or other user in aradially outward direction perpendicular or oblique to the longitudinalaxis 262 (for example, in the direction of arrow 229) to split thetubular sheath 212A. Pulling the wire 220 in this manner pulls the wire220 out of the wall 284, thereby breaking the wall and splitting thetubular sheath 212A into the two sides 268, 270 of the tubular sheath212A, such that the inner lumen 292 of the tubular sheath 212A isexposed. Once split, the tubular sheath 212A may be removed from thecatheter 16 (e.g., in a radial or transverse direction with reference tothe longitudinal axis 262 of the tubular sheath 212A). In this way, thetubular sheath 212A including the wire 220 is configured to enclose theexpandable balloon 14 until the expandable balloon 14 is inserted intothe introducer sheath 22 while also being configured to be splittable,enabling the tubular sheath 212A to be removed from the catheter 16 oncethe expandable balloon 14 is sufficiently inserted.

FIG. 4A is a conceptual and schematic diagram illustrating a side viewof a tubular sheath 212B including a longitudinal splitting element thatincludes one or more longitudinal holes 240A-240D (collectively,“longitudinal holes 240”). The longitudinal holes 240 may extend from aproximal end 264 of the tubular sheath 212B to a distal end 266 of thetubular sheath 212B. The longitudinal holes 240 may define any shape incross-section. In some examples, longitudinal holes 240 may define acircular cross-section, which may be more easily manufactured. Thelongitudinal holes 240 may have a consistent cross-sectional shape alongthe length of tubular sheath 212B. The longitudinal holes 240 may beformed in the tubular sheath 212B using any suitable technique, such asextrusion or laser cutting. The longitudinal holes 240 may besubstantially parallel with the longitudinal axis 262 of the tubularsheath 212B.

In some examples, in addition to the longitudinal holes 240, the tubularsheath 212B may define a longitudinal groove 242 that extends radiallyin from the outer wall 286 of the tubular sheath 212B. The longitudinalgroove 242 may extend from a proximal end 264 of the tubular sheath 212Bto a distal end 266 of the tubular sheath 212B. The longitudinal groove242 may preferably radially align with one or more longitudinal holes240. Such alignment with the longitudinal groove 242 may facilitateidentifying the longitudinal holes 240. For example, where a clinicianmay have otherwise encountered some difficulty locating the longitudinalholes 240 (e.g., as the longitudinal holes 240 are internal features),the longitudinal groove 242 may provide a readily identifiable externalfeature to locate the longitudinal holes 240. The longitudinal groove242 may additionally facilitate more easily splitting the tubular sheath212B. For example, in some situations the tubular sheath 212B may besufficiently weakened such that the tubular sheath 212B may be readilysplit as discussed herein because the tubular sheath 212B includes boththe longitudinal holes 240 and the longitudinal groove 242. However, inother examples the longitudinal holes 240 and/or longitudinal groove 242alone may be sufficient to configure the tubular sheath 212B to besplittable.

In some examples, the tubular sheath 212B may be formed with thelongitudinal groove 242. For example, the tubular sheath 212B may beformed using a mold or other tooling (e.g., a nozzle of an extruder)that defines the longitudinal groove 242. In other examples, thelongitudinal groove 242 may be formed into the tubular sheath 212B afterthe tubular sheath 212B is formed using any suitable technique. Forexample, the longitudinal groove 242 may be longitudinally cut into thetubular sheath 212B using a laser cutter, or the longitudinal groove 242may be radially cut using a mill or other cutting tool.

FIG. 4B is a conceptual and schematic diagram illustrating across-sectional view of the tubular sheath 212B, the longitudinal holes240, and the longitudinal grooves 242A, 242B (collectively “longitudinalgrooves 242”) as viewed at the cross-sectional cut plane 248. ThoughFIG. 4B depicts four longitudinal holes 240 and two longitudinal grooves242, other examples may include more or fewer longitudinal holes, moreor fewer longitudinal grooves 242, or both. Each longitudinal groove ofthe longitudinal grooves 242 may be substantially aligned with one ormore hole of the longitudinal holes 240.

For example, longitudinal groove 242A is radially aligned withlongitudinal holes 240A, 240B, and longitudinal groove 242B is radiallyaligned with longitudinal holes 240C, 240D. As depicted, thelongitudinal groove 242A and longitudinal holes 240A, 240B may all becentered on a radial line 244 that extends radially outward from thelongitudinal axis 262 of the tubular sheath 212B. The tubular sheath212B may define one or more longitudinal holes 240 that are radiallyin-line with the longitudinal groove 242, such that longitudinal holes240 are closer to the longitudinal axis 262 of the tubular sheath 212Bthan the longitudinal groove 242.

Further, in examples in which there are more than one set oflongitudinal holes 240 (e.g., more than one radially-aligned set ofholes 240 in the tubular sheath 212B) as in longitudinal holes 240A,240B and longitudinal holes 240C, 240D of FIG. 4A, the sets oflongitudinal holes 240 may be arranged evenly throughout the tubularsheath 212B around the circumference of the tubular sheath 212B. Forexample, if there are two sets of longitudinal holes 240 in the tubularsheath 212B, the two sets of longitudinal holes 240 may be arranged 180°away from each other around the circumference of the tubular sheath212B, as shown in FIG. 4B. Alternatively, if there were three or foursets of longitudinal holes 240 in the tubular sheath 212B, the three orfour sets of longitudinal holes 240 may be arranged 120° or 90° degreesapart around the longitudinal axis 262, respectively. Such a dispersionof multiple sets of longitudinal holes 240 may enable a clinician tomore easily split the tubular sheath 212B without having to think aboutthe orientation of the longitudinal holes 240, and thus save proceduretime. Additionally, by including a plurality of longitudinal hole 240sets, the tubular sheath 212B may enable a clinician to select the sizeof an opening to the inner lumen 292 that would be created uponsplitting the tubular sheath 212B (e.g., by selecting different sets oflongitudinal holes 240 along which the tubular sheath 212B may besplit). By enabling a clinician to select the size of an opening to theinner lumen 292, the tubular sheath 212B may enable a clinician tominimize an amount of contact between the catheter 16 and tubular sheath212B when the tubular sheath 212B, therein reducing an element ofprocedural complexity.

The longitudinal holes 240 and the longitudinal grooves 242 areconfigured to enable the tubular sheath 212B to be split in response toapplication of a force above a threshold force as discussed herein. Forexample, a user such as a clinician may apply the force as a shearing ortearing force along the radial line 244. As discussed above, thelongitudinal groove 242 may enable a clinician to identify thelongitudinal holes 240 and radial line 244 in which the clinician mayapply the force. The longitudinal holes 240 and longitudinal groove 242may define a structurally weak portion of the tubular sheath 212B alongthe radial line 244 that includes the longitudinal holes 240 andlongitudinal groove 242, therein enabling the tubular sheath 212B to besplit in response to application of the force above the threshold forceby a user. For example, the tubular sheath 212B may be stressedimmediately adjacent to the longitudinal holes 240 and longitudinalgroove 242, such as in the direction of arrow 250 to create a shearingor tearing force that substantially aligns with the radial line 244 thatintersects the longitudinal holes 240 and longitudinal groove 242. Theforce may be applied using a tab 246 that is attached to the outer wall286 of the tubular sheath 212B adjacent to the longitudinal groove 242on the proximal end 264 of the tubular sheath 212B. In other examples,the tab 246 may be located additionally or alternatively on the distalend 266 of the tubular sheath 212B. The tab 246 may be configured toretain a connection to the outer wall 286 in response to a force thatgreatly exceeds the threshold force, so that the tab 246 may facilitatestressing of the longitudinal holes 240 and longitudinal groove 242 tosplit the tubular sheath 212B. In other examples, the tubular sheath 212may include two tabs 246, one on either side of the longitudinal groove242. In still further examples, the tubular sheath 212B may omit the tab246 and a clinician or other user may grab the tubular sheath on eitherside of the longitudinal holes 240.

Thus, when the tubular sheath 212B is on the expandable balloon 14, thetubular sheath 212B encloses at least a portion of the expandableballoon 14, but once the expandable balloon 14 is inserted into apatient 26 (FIG. 1A) a clinician may apply a force radially on thelongitudinal groove 242 and/or longitudinal holes 240 to split thetubular sheath 212B. Applying the force radially on the longitudinalholes 240 and or the longitudinal groove 242 splits the tubular sheath212B into the two sides 268, 270 of the tubular sheath 212B, such thatthe inner lumen 292 of the tubular sheath 212B is exposed. Once split, aclinician may remove the tubular sheath 212B from the catheter 16 (e.g.,in a radially outward or transverse direction). In this way, the tubularsheath 212B with the longitudinal holes 240 and/or the longitudinalgroove 242 is configured to enclose the expandable balloon 14 until theexpandable balloon 14 is inserted while also being configured to besplittable, enabling the tubular sheath 212B to be removed from thecatheter 16 once the expandable balloon 14 is sufficiently inserted.

Alternatively, as discussed above, a tubular sheath 12 may include agripping portion rather than (or potentially in addition to) alongitudinal splitting element 160. For example, FIGS. 5A-5C areconceptual and schematic diagrams illustrating an example tubular sheath312, including a side view (FIG. 5A), a cross-sectional view taken alongline 374 (FIG. 5B), and a side view in an open configuration (FIG. 5C).The tubular sheath 312 may be substantially similar to the tubularsheaths 12 and 112 of FIGS. 1A-2D, aside from the differences describedherein.

The tubular sheath 312 may include a gripping portion 350. The grippingportion 350 may be a section of the wall of the tubular sheath thatextends from a proximal end 364 of the tubular sheath 312 to a distalend 366 of the tubular sheath 312 and is configured to be pulled awayand out from the tubular sheath to split open the tubular sheath 312.The gripping portion 350 is configured to have relatively poor cohesivestrength to adjacent portion 378, 380 of the tubular sheath 312. Forexample, the gripping portion 350 may be lined with a plurality ofperforations (e.g., similar to the tubular sheath 412A of FIGS. 6A and6B as described below). In such examples, the gripping portion 350 mayhave relatively poor cohesive strength to adjacent portions 378, 380 asa result the perforations that divide the gripping portion 350 from theadjacent portions 378, 380. For another example, the gripping portion350 may be made of a different material than the tubular sheath 312(e.g., similar to the tubular sheath 412B of FIGS. 7A and 7B asdescribed below). In such an example, the two materials will bond toeach other to provide a closed tubular sheath 312, but the bond strengthwill be such that a sufficient force will break the bond. In one suchexample, the tubular sheath 312 may be made of HDPE, while the grippingportion 350 may be made of PEBAX® (thermoplastic elastomers availablefrom Arkema, Colombes, France), which does not bond strongly to HDPE. Inanother example, the gripping portion 350 may be attached to the tubularsheath 312 in such a way as to produce a weak bond, such as anultrasonic weld at a relatively suboptimum frequency, a chemical bondwith a relatively weak adhesive, a solvent bond using a solvent thatwill soften the materials without producing a relatively strong bond, orco-extruding the gripping portion 350 and the tubular sheath 312 at arelatively suboptimum temperature. As depicted in FIG. 5A, the grippingportion 350 may be substantially parallel with a longitudinal axis 362of the tubular sheath 312. In other examples, the gripping portion 350may be at a fixed or varying angle relative to the longitudinal axis 362as the gripping portion 350 extends between the proximal end 364 anddistal end 366 of the tubular sheath 312 (e.g., similar to how thelongitudinal splitting element 160 spirals around the tubular sheath 212in FIG. 2B).

It is to be understood that the depicted amount of the tubular sheath312 that includes the gripping portion 350 within FIGS. 5A and 5B is forpurposes of illustration only. In other examples, the gripping portion350 may include more or less of the tubular sheath 312. The amount ofthe tubular sheath 312 that includes the gripping portion 350 isconfigured to enable the grasping and pulling of the gripping portion350 away from the tubular sheath 312. As such, it may be advantageous toconfigure the gripping portion 350 to include a relatively small amount(e.g., less than 45%) of the tubular sheath 312 to facilitate suchgrasping and pulling.

As depicted in FIG. 5B, the gripping portion 350 may extend from aninner wall 388 of the tubular sheath 312 to an outer wall 386 of thetubular sheath 312. The gripping portion 350 may extend from the outerwall 386 to the inner wall 388 for the majority or the entirety of thelength of the tubular sheath 312. As depicted in FIG. 5B, perimeterwalls 352A, 352B (collectively, “perimeter walls 352) of the grippingportion 350 may extend radially straight in towards the longitudinalaxis 362 of the tubular sheath 312. In other examples, the perimeterwalls 352 of the gripping portion 350 may extend from the outer wall 386to the inner wall 388 at an angle other than substantially straightradially inwards towards the longitudinal axis 362 to create a moreacute or obtuse angle with the inner wall 388. The angles of theperimeter walls 352 may impact an amount of cohesive strength that thegripping portion 350 has to the adjacent portions 378, 380. For example,if the perimeter walls 352 extend to the inner wall 388 with arelatively acute angle, the gripping portion 350 may have relativelyless cohesive strength to adjacent portions 378, 380 (e.g., such that itis relatively easier to pull the gripping portion 350 from tubularsheath 312), whereas if the perimeter walls 352 extend to the inner wall388 with a relatively obtuse angle, the gripping portion 350 may haverelatively more cohesive strength to adjacent portions 378, 380 (e.g.,such that it is relatively harder to pull the gripping portion 350 fromtubular sheath 312).

The tubular sheath 312 is in an enclosing configuration 394 whileenclosing the expandable balloon 14 on the catheter 16. The grippingportion 350 is configured to split open the tubular sheath 312 into asplit configuration, such as the split configuration 396 of FIG. 5C. Tosplit the tubular sheath 312, a user such as a clinician may hold thegripping portion 350 and pull it radially away from the tubular sheath312, such as along arrow 355. When split using the gripping portion 350,the tubular sheath 312 may split along the adjacent portions 378, 380,with the gripping portion 350 being substantially removed from thetubular sheath 312, or the tubular sheath 312 may split along only oneof the adjacent portions 378, 380. The split configuration 396 exposesthe inner lumen 392 such that the tubular sheath 312 may be removed fromthe catheter 16. The tubular sheath 312 is configured to stay in theenclosing configuration 394 while the expandable balloon 14 is beinginserted into the vasculature 24 of a patient 26 (FIG. 1A), as discussedherein.

FIGS. 6A-7B relate to tubular sheaths 412A, 412B (collectively, “tubularsheaths 412”) that include gripping portions 350. The tubular sheaths412 may be substantially similar to the tubular sheath 12, 112, 212, 312of FIGS. 1A-5C aside from the differences described herein. FIG. 6A is aconceptual and schematic diagram illustrating a side view of a tubularsheath 412A that includes an example perforated gripping portion 420.The perforated gripping portion 420 may be a longitudinal segment orportion of the tubular sheath 412A that is perforated to facilitate theperforated gripping portion 420 being pulled out from the tubular sheath412A, such as in the direction of arrow 425. The perforated grippingportion 420 may extend from a proximal end 464 of the tubular sheath412A to a distal end 466 of the tubular sheath 412A. In some examples,the perforated gripping portion 420 may extend through the tubularsheath 412A substantially parallel with the longitudinal axis 462 of thetubular sheath 412A. In other examples (not depicted), the perforatedgripping portion 420 may extend through the tubular sheath 412A at anangle to or in a spiral around the longitudinal axis 462 on the tubularsheath 412A (e.g., similar to FIG. 2B).

The perforated gripping portion 420 may have a relatively poor cohesivestrength to adjacent portion 478, 480 of the tubular sheath 412A as aresult of a plurality of perforations 422. The plurality of perforations422 may extend from the proximal end 464 of the tubular sheath 412A tothe distal end 466 of the tubular sheath 412A. The plurality ofperforations 422 may be located at the nexuses between the perforatedgripping portion 420 and the adjacent portions 478, 480 of the tubularsheath 412A. The length of and spacing between perforations 422 depictedin FIG. 6A is for purposes of illustration only; other lengths andspaces between perforations 422 that result in the configurationsdiscussed herein are also possible. Each perforation 422 may cutsubstantially through one side of the tubular sheath 412A. In someexamples, the tubular sheath 412A is constructed as a unitary structurewithout perforations 422, such that the perforations 422 are radiallycut into the tubular sheath 412 post-construction to define theperforated gripping portion 420. The plurality of perforations 422enable the perforated gripping portion 420 to be pulled out (e.g.,removed) from the tubular sheath 412A in response to a force (e.g.,arrow 425) above a threshold force as discussed herein. Pulling theperforated gripping portion 420 from the tubular sheath 412A result inthe tubular sheath 412A being split, such that the tubular sheath 412Amay be removed from the catheter 16.

In some examples, the perforated gripping portion 420 may include a tab424 upon which the force above the threshold force may be applied. Thetab 424 may extend proximally from the proximal end 464 of the tubularsheath 412A. In other examples, a tab 424 may alternatively oradditionally extend distally from the distal end 466 of the tubularsheath 412A. The tab 424 may have a relatively strong cohesive bond to,or be formed integrally with, the perforated gripping portion 420, suchthat the tab 424 may remain securely attached to the perforated grippingportion 420 in response to a force far greater than the threshold force,so that the tab 424 is configured to remain attached to the perforatedgripping portion 420 when the force greater than the threshold force isapplied to the tab 424. In some examples, the tubular sheath 412A mayomit the tab 424 and a user such as a clinician may apply the forcedirectly to the perforated gripping portion 420.

FIG. 6B is a conceptual and schematic diagram illustrating across-sectional view of the tubular sheath 412A of FIG. 6A as viewedfacing the cross-sectional cut-plane 426. As depicted in FIG. 6B, theperforations 422 extend radially from an inner surface 488 of thetubular sheath 412A to an outer surface 486 of the tubular sheath 412A.A user applying the force above the threshold force to the incongruousgripping portion 440 results in the tubular sheath 412A splitting opensuch that the inner lumen 492 is exposed.

Thus, when the tubular sheath 412A is around the expandable balloon 14,the tubular sheath 412A encloses at least a portion of the expandableballoon 14, but once the expandable balloon 14 is inserted, a user mayapply the force to the perforated gripping portion 420 (e.g., using atab 424) to split the tubular sheath 412A. As a result of a userapplying the force to the perforated gripping portion 420 in an outwardradial direction (e.g., relative to the tubular sheath 412A), such asalong arrow 425, the tubular sheath 412A may split between the twoportions 478, 480 of the tubular sheath 412A, such that the inner lumen492 of the tubular sheath 412A is exposed. Once split, a user may removethe tubular sheath 412A from the catheter 16 (e.g., in a radiallyoutward or transverse direction). In this way, the tubular sheath 412Awith the perforated gripping portion 420 is configured to enclose theexpandable balloon 14 until the expandable balloon 14 is inserted intothe introducer sheath while also being configured to be splittable,enabling the tubular sheath 412A to be removed from the catheter 16 oncethe expandable balloon 14 is sufficiently inserted.

FIG. 7A is a conceptual and schematic diagram illustrating a side viewof an example tubular sheath 412B with yet another example grippingportion 350. The gripping portion 350 of FIG. 7A may be an incongruousgripping portion 440 that is made from a different material than therest of the tubular sheath 412B. The incongruous gripping portion 440may extend from a proximal end 464 of the tubular sheath 412B to adistal end 466 of the tubular sheath 412B. In some examples, theincongruous gripping portion 440 may longitudinally extend along thetubular sheath 412B substantially in parallel with the longitudinal axis462 of the tubular sheath 412B. In other examples (not depicted), theincongruous gripping portion 440 may extend through the tubular sheath412B at an angle to or even in a spiral around the longitudinal axis 462on the tubular sheath 412B.

The incongruous gripping portion 440 may have a relatively poor cohesivestrength to adjacent portions 268, 270 of the tubular sheath 412B. Therelatively poor cohesive strength may be a result of the incongruousgripping portion 440 including a first material and the adjacentportions 478, 480 of the tubular sheath 412B including a secondmaterial. In some examples, the first material and second material mayhave a relatively poor bond to each other (e.g., the first material isHDPE and the second material is pebax or nylon), such that the firstmaterial would pull away from the second material in response to a forcegreater than the threshold force as discussed herein. Alternatively, thefirst material may have a greater density and/or tensile strength thanthe second material (e.g., the first material is HDPE and the secondmaterial is LDPE), such that the first material tears or breaks beforethe second material in response to the force greater than the thresholdforce as discussed herein. The tubular sheath 412B may be constructed ina single operation. For example, the incongruous gripping portion 440and the adjacent portions 478, 480 may be co-extruded using twodifferent materials as described above, such that the tubular sheath412B, including the incongruous gripping portion 440, is fullyconstructed after the single extrusion process.

In certain examples, the incongruous gripping portion 440 may include atab 442 attached to the incongruous gripping portion 440 at the proximalend 464 of the tubular sheath 412B. The tab 442 may be configured tofacilitate the removal of the incongruous gripping portion 440 from thetubular sheath 412B. In other examples, a tab 442 may alternatively oradditionally be connected to the incongruous gripping portion 440 at thedistal end 466 of the tubular sheath 412B.

FIG. 7B is a conceptual and schematic diagram illustrating across-sectional view of the tubular sheath 412B of FIG. 7B taken alongcross-sectional cut-plane 444. As depicted in FIG. 7B, the incongruousgripping portion 440 may extend radially from an inner surface 488 ofthe tubular sheath 412B to an outer surface 486 of the tubular sheath412B. In some examples, the incongruous gripping portion 440 may have adifferent appearance (e.g., be colored differently, textureddifferently, have a different opacity, or the like) than the rest of thetubular sheath 412B. Forming the incongruous gripping portion 440 with adifferent appearance relative to the rest of the tubular sheath 412B mayprovide benefits in identifying the incongruous gripping portion 440. Insome examples, the entirety of the tubular sheath 412B may define adifferent appearance than the incongruous gripping portion 440, asdepicted in FIG. 7B. In other examples, only an outer surface 446 of theincongruous gripping portion 440 may be a different appearance than anouter surface 486 of the tubular sheath 412B.

Thus, when the tubular sheath 412B is on the expandable balloon 14, thetubular sheath 412B encloses at least a portion of the expandableballoon 14, but once the expandable balloon 14 is inserted in to theintroducer sheath 22 a clinician may apply a force to the incongruousgripping portion 440 (e.g., using a tab 442) to split the tubular sheath412B. Applying the force to the incongruous gripping portion 440radially away from the tubular sheath 412B, such as shown by arrow 455,splits the tubular sheath 412B between the two portions 478, 480 of thetubular sheath 412B, such that the inner lumen 492 of the tubular sheath412B is exposed. Once split, the tubular sheath 412B may be removed fromthe catheter 16 (e.g., in a radially outward or transverse direction).In this way, the tubular sheath 412B with the incongruous grippingportion 440 is configured to enclose the expandable balloon 14 until theexpandable balloon 14 is inserted into the introducer sheath 22 whilealso being configured to be splittable, enabling the tubular sheath 412Bto be removed from the catheter 16 once the expandable balloon 14 issufficiently inserted.

FIG. 8 is a flow diagram illustrating an example method of insertingexpandable balloons 14 using tubular sheaths 12. Although FIG. 8 will bedescribed with reference to the medical device 10 and other componentsillustrated in FIGS. 1A-1D, it will be appreciated that the technique ofFIG. 8 may be used with any of the medical devices described herein. Theflow diagram of FIG. 8 is discussed in conjunction with FIGS. 9A-9C forpurposes of clarity.

A clinician may position a distal portion 18 of a medical device 10 neara patient 26 (500). In some examples, the clinician may position thedistal portion 18 of the medical device 10 near an introducer sheath 22that is inserted within the patient 26. The clinician may distally movethe catheter 16, expandable balloon 14, and the tubular sheath 12 inconjunction as the distal portion 18 is positioned near the introducersheath 22. The introducer sheath 22 may terminate in vasculature 24 ofthe patient 26. The clinician may position/guide the distal portion 18of the medical device 10 near the introducer sheath 22 using a guidewire20 that extends proximally from the introducer sheath 22. For example,the clinician may insert the guidewire 20 into the guidewire lumen 42 ofthe catheter 16.

In FIG. 9A, a clinician mates the distal end 66 of the tubular sheath 12with the introducer sheath 22. The tubular sheath 12 may stably receiveor be stably received by the introducer sheath 22 (e.g., using a Luerconnection) to ensure a solid transfer of the expandable balloon 14. Insome examples, the distal end 66 of the tubular sheath 12 may act as aLuer connector that engages a Luer connection of the introducer sheath22 (e.g., internal threads 182 of the tubular sheath 12 may be threadedonto threads 23 of the introducer sheath 22 as the introducer sheath 22is received by the tubular sheath 12).

The clinician may push the expandable balloon 14 through the tubularsheath 12 into the introducer sheath 22 (502). The clinician may pushthe expandable balloon 14 into the introducer sheath 22 by distallypushing the catheter 16 and/or catheter 16 hub 38. The clinician mayadvance the expandable balloon 14 and catheter 16 over the guidewire 20into the introducer sheath 22 while the tubular sheath 12 remainsstationary (e.g., stationary relative to the catheter 16 and expandableballoon 14) as depicted in FIG. 9B. In some examples, the clinician mayadvance the expandable balloon 14 and catheter 16 in response to thetubular sheath 12 being stably received by the introducer sheath 22(e.g., using a Luer connection). In this way, the clinician may insertthe expandable balloon 14 into the introducer sheath 22 and thereinintroduce the expandable balloon 14 to the vasculature 24 of a patient26 without manually handling or otherwise having an external surface 48of the expandable balloon 14 contacted in a notable manner. The tubularsheath 12 thus is configured to avoid substantially all contact with theexpandable balloon 14 while the expandable balloon is being inserted.

Once the expandable balloon 14 is entirely within the introducer sheath22/patient 26/vasculature 24, the clinician may slide the tubular sheath12 proximally on the catheter 16. The catheter 16 remains substantiallystationary while the clinician slides the tubular sheath 12 proximallyalong the catheter 16. In some examples, the clinician may slide thetubular sheath 12 proximally up to the hub 38 of the catheter 16.

As shown in FIG. 9C, the clinician then splits open the tubular sheath12 (504). In some example procedures, the clinician may split open thetubular sheath 12 in response to fully inserting the expandable balloon14 into the introducer sheath 22 and proximally sliding the tubularsheath 12.

The clinician may remove the tubular sheath 12 by converting the tubularsheath 12 into an open configuration by splitting the tubular sheath 12open using a longitudinal splitting element 160 or gripping portion 350.In some examples, the clinician splits open the tubular sheath 12 byapplying a force greater than a threshold force to a longitudinalsplitting element 160 within the wall 184 of the tubular sheath, asexplained above with reference to the various examples. In otherexamples, the clinician splits the tubular sheath 12 by applying a forcegreater than a threshold force upon a gripping portion 350 of thetubular sheath 12 that has poor cohesive strength to adjacent portions378, 380 of the tubular sheath 12, as explained above with reference tothe various examples. The clinician splits the tubular sheath 12 toexpose the inner lumen 192 of the tubular sheath 12 (i.e., convertingthe tubular sheath 12 into an open configuration). Upon exposing theinner lumen 192 of the tubular sheath 12, the clinician may remove thetubular sheath 12 from the catheter 16 (506).

Various examples of the disclosure have been described. These and otherexamples are within the scope of the following claims.

What is claimed is:
 1. A medical device comprising: a catheterconfigured to navigate vasculature of a patient after insertion throughan introducer sheath inserted in the patient, the catheter comprising adistal portion and a proximal portion; an expandable balloon that isattached to the distal portion of the catheter; and a tubular sheathconfigured to enclose the expandable balloon, wherein the tubular sheathcomprises at least one longitudinal splitting element within a wall ofthe tubular sheath, the at least one longitudinal splitting elementbeing configured to split the wall of the tubular sheath in response toa force greater than a threshold force upon the at least onelongitudinal splitting element, wherein the at least one longitudinalsplitting element extends from a proximal end of the tubular sheath to adistal end of the tubular sheath.
 2. The medical device of claim 1,wherein the at least one longitudinal splitting element comprises a wireembedded longitudinally along a length of the tubular sheath, the wireconfigured to extend out from at least one of the proximal end anddistal end of the tubular sheath, wherein the wire is configured tosplit the tubular sheath as a result of pulling the wire out from thewall.
 3. The medical device of claim 2, further comprising a tab that isattached to an end of the wire that extends out from the at least oneend of the tubular sheath.
 4. The medical device of claim 1, wherein theat least one longitudinal splitting element comprises two or more setsof holes that extend longitudinally through a wall of the tubular sheathfrom the proximal end of the tubular sheath to the distal end of thetubular sheath, wherein the two or more sets of holes are configured tosplit the tubular sheath as a result of stressing the tubular sheathalong the two or more sets of holes.
 5. The medical device of claim 4,wherein each set of holes includes two or more holes that are arrangedradially from an inner surface of the tubular sheath to an outer surfaceof the inner sheath.
 6. The medical device of claim 5, wherein thetubular sheath comprises one or more grooves that extend radially infrom an outer surface of the tubular sheath and extend longitudinallyfrom the proximal end of the tubular sheath to the distal end of thetubular sheath, wherein each groove is radially in-line with one of thetwo or more sets of holes.
 7. The medical device of claim 4, whereinsets of holes are arranged 180° apart across the longitudinal axis ofthe tubular sheath.
 8. The medical device of claim 1, wherein thetubular sheath comprises at least one of poly(tetrafluoroethylene), highdensity polyethylene, or low density polyethylene.
 9. The medical deviceof claim 1, wherein a thickness of the wall of the tubular sheath issubstantially constant throughout the tubular sheath.
 10. The medicaldevice of claim 1, further comprising a luer fitting at a distal end ofthe tubular sheath, wherein the luer fitting comprises a structuralweakness aligned with the at least one longitudinal splitting element toenable the luer fitting to be controllably split along the structuralweakness.
 11. The medical device of claim 1, wherein the tubular sheathis configured to be received by the introducer sheath during insertionof the catheter into the introducer sheath such that the tubular sheathremains stationary relative to the introducer sheath while slidingproximally relative to the catheter as the catheter is inserted distallyat least until the expandable balloon is fully inserted into theintroducer sheath without substantial contact between the tubular sheathand the expandable balloon.
 12. A medical device comprising: a catheterconfigured to navigate vasculature of a patient after insertion into anintroducer sheath inserted in the patient, the catheter comprising adistal portion and a proximal portion; an expandable balloon that isattached to the distal portion of the catheter; and a tubular sheathcomprising a gripping portion, wherein: the tubular sheath is configuredto enclose the expandable balloon, the gripping portion of the tubularsheath has relatively poor cohesive strength to adjacent portions of thetubular sheath such that the tubular sheath is configured to be splitalong the gripping portion to enable the tubular sheath to be splittablyremovable from the catheter, the gripping portion of the tubular sheathextends from a proximal end of the tubular sheath to a distal end of thetubular sheath, the gripping portion of the tubular sheath extendsthrough a thickness of a wall of the tubular sheath.
 13. The medicaldevice of claim 12, wherein an external surface of the expandableballoon comprises a drug coating.
 14. The medical device of claim 12,wherein the expandable balloon is in a deflated state on the distalportion of the catheter, a diameter of the inner lumen of the tubularsheath configured to be greater than an outer diameter of the expandableballoon in the deflated state.
 15. The medical device of claim 14,wherein a length of the tubular sheath along the longitudinal axis ofthe tubular sheath is greater than a length of the expandable balloonalong a longitudinal axis of the expandable balloon in the deflatedstate.
 16. The medical device of claim 12, wherein the expandableballoon is a percutaneous transluminal angioplasty (PTA) balloon. 17.The medical device of claim 12, wherein the gripping portion of thetubular sheath comprises a first material and adjacent portions of thetubular sheath comprise a second material, wherein the first and secondmaterial are configured to have a relatively poor bond to each other,wherein the tubular sheath is configured to be splittable as a result ofpulling the gripping portion away from the adjacent portions.
 18. Themedical device of claim 17, further comprising a tab that is attached tothe gripping portion of the tubular sheath at an end of the grippingportion to facilitate pulling of the gripping portion.
 19. The medicaldevice of claim 17, wherein the first material is a different color thanthe second material.
 20. The medical device of claim 12, wherein thegripping portion of the tubular sheath comprises a first material andadjacent portions of the tubular sheath comprise a second material, thefirst material having a greater tensile strength than the secondmaterial.
 21. The medical device of claim 20, further comprising a tabthat is attached to the gripping portion of the tubular sheath on an endof the gripping portion to facilitate pulling of the gripping portion.22. The medical device of claim 12, wherein the gripping portion and theadjacent portions converge at two parallel lines of perforations thatextend longitudinally from the proximal end of the tubular sheath to thedistal end of the tubular sheath, wherein each line of perforation cutsthrough the wall of the tubular sheath, the medical device furthercomprising a tab that is attached to the proximal or distal end of thegripping portion, wherein the tubular sheath is configured to besplittable as a result of pulling the tab and disengaging the firstmaterial from the second material.
 23. The medical device of claim 12,wherein the tubular sheath is configured to be received by theintroducer sheath during insertion of the catheter into the introducersheath such that the tubular sheath remains substantially stationaryrelative to the introducer sheath while sliding proximally relative tothe catheter as the catheter is inserted distally at least until theexpandable balloon is fully inserted into the introducer sheath withoutsubstantial contact between the tubular sheath and the expandableballoon.
 24. A method of inserting expandable balloons, the methodcomprising: locating a distal portion of a catheter of a medical deviceimmediately proximal to an introducer sheath inserted in a patient, themedical device comprising: an expandable balloon that is attached to thedistal portion of the catheter, and a tubular sheath configured toenclose the expandable balloon, wherein a gripping portion of thetubular sheath has relatively poor cohesive strength to adjacentportions of the tubular sheath such that the tubular sheath isconfigured to be split along the gripping portion to enable the tubularsheath to be splittably removable from the catheter, the grippingportion of the tubular sheath extends from a proximal end of the tubularsheath to a distal end of the tubular sheath, the gripping portion ofthe tubular sheath extends through a thickness of a wall of the tubularsheath, distally pushing the catheter into the introducer sheath suchthat the tubular sheath remains stationary relative to the introducersheath while sliding proximally relative to the catheter as the catheteris inserted distally at least until the expandable balloon is fullyinserted into the introducer sheath without substantial contact betweenthe tubular sheath and the expandable balloon; and splitting the tubularsheath using the gripping portion to remove the tubular sheath from thecatheter in response to fully inserting the expandable balloon into theintroducer sheath.
 25. A method of inserting expandable balloons, themethod comprising: locating a distal portion of a catheter of a medicaldevice immediately proximal to an introducer sheath inserted in apatient, the medical device comprising: an expandable balloon that isattached to the distal portion of the catheter, and a tubular sheathconfigured to enclose the expandable balloon, wherein the tubular sheathcomprises at least one longitudinal splitting element within a wall ofthe tubular sheath, the at least one longitudinal splitting elementbeing configured to split the wall of the tubular sheath in response toa force greater than a threshold force upon the at least onelongitudinal splitting element, wherein the at least one longitudinalsplitting element extends from a proximal end of the tubular sheath to adistal end of the tubular sheath, distally pushing the catheter into theintroducer sheath such that the tubular sheath remains stationaryrelative to the introducer sheath while sliding proximally relative tothe catheter as the catheter is inserted distally at least until theexpandable balloon is fully inserted into the introducer sheath withoutsubstantial contact between the tubular sheath and the expandableballoon; and splitting the tubular sheath using the at least onelongitudinal splitting element to remove the tubular sheath from thecatheter in response to fully inserting the expandable balloon into theintroducer sheath.